This invention relates to fences, and more particularly to a silt fence support.
Construction often disturbs trees, grasses, bushes and other elements, which naturally control run-off, water, sediment and erosion, and result in unprotected banks of soil. Typically, the bare earth is exposed in a construction site, which, if no controls are implemented, causes significant erosion and other water damage can occur. When unprotected banks are subjected to water flow, as during a rain storm, the run-off of ground water carries with it substantial amounts of silt, fine soil, stones and the like. This action results in erosion of the banks and, in addition, causes the file particles to flow along with the water causing contamination of streams, ponds, private property and vegetation.
Silt fences are used as barriers to sediment, particularly in connection with preventing soil erosion at construction sites. Silt fences prevent sediments carried by un-channeled flow, or sheet flow, from rainwater from leaving a ground site and either entering natural drainage channels or entering waste and storm drain systems. Un-channeled surface water that is deposited upon ground having a sloped surface moves by gravity directed flow along paths determined by the contour of the ground surface. Typically, a silt fence is installed along a path spanning the sloped ground surface or along a path spanning beneath such a slope. The installation path is selected such that it is transverse to the water flow path and impedes the flow. The barriers slow the runoff sheet flow and frequently create a ponding of water upstream of the silt fence. The reduction in water velocity causes the larger entrained soil particles to settle to the ground surface upstream of the silt fence. A silt fence provides a filtration barrier that filters suspended silt particles as the low velocity of ponded water passes through the silt fence to form an effluent stream. The filtered silt particles are shed from the vertical fabric barrier surface or the standard silt fence and accumulate at its base. The size of openings in the barrier determines the size of the particles filtered. The size, shape and number of openings, as well as the height of the ponded water, determine flow rate of the filtered effluent stream.
A wide variety of materials and structures are used in sediment control barriers. Sediment control barriers include silt fences constructed of filtering fabrics, support posts and wire fences. Conventional silt fences are constructed of flexible plastic material attached to wooden stakes, which are driven into the ground. However, this construction generally does not have the structural strength to collect soil and sediment, and is susceptible to adverse effects produced by the wind. The wind causes the fencing material to pull at the attachment and eventually it becomes torn and does not function for the purposes intended.
Another type of sediment and erosion control device uses a base comprised of hay or straw bales. However, hay bales are seldom satisfactory. Firstly, they are difficult to install. The weight and associated factors of hay bales make installation a labor-intensive task. Secondly, long wooden or steel stakes must be used to hold the bales in place. These are expensive and difficult to install and remove. Thirdly, quality control for hay or straw bales is very seldom available, resulting in a poor quality material often being used. Fourthly, hay or straw bales become soil laden very quickly and cannot be reused. The bales disintegrate in a relatively short period of time. They are then difficult to remove. Finally, hay bales are not readily available in some areas and, due to their weight and bulkiness, cannot be shipped to these areas in a cost-efficient manner.